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<p>Hi John,</p>
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<p>I encountered a similar problem a while ago and realized that depending on a combination of different settings in the memory options (option_savetwofiles, option_single), the precision of the data potentially changes when saving a dataset (single vs. double).</p>
<p>The precision, in turn, appears to affect the result returned by <em>rank(EEG.data)</em>. For double precision, the rank corresponded to the number of channels; when converting the same data to single precision, the rank changed to a comparatively low value
(similar to what you report).</p>
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<p>You could check the precision before and after saving the dataset; maybe your problem is related to this aspect?<br>
</p>
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<p>Best,</p>
<p>Hannah <br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" color="#000000" face="Calibri, sans-serif"><b>Von:</b> eeglablist <eeglablist-bounces@sccn.ucsd.edu> im Auftrag von Johnson, John T. <john.johnson@gatech.edu><br>
<b>Gesendet:</b> Mittwoch, 16. Mai 2018 20:24<br>
<b>An:</b> eeglablist@sccn.ucsd.edu<br>
<b>Betreff:</b> [Eeglablist] Saving data set changes rank</font>
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<div class="">When I load a data set, the rank of the data is 58, the same as the number of channels.</div>
<div class="">Making no changes and saving the data set with another name, the rank changes to 1.</div>
<div class="">I like saving data at various check points while preprocessing, and this change in rank can affect specifying rank for the pca option to ica, or pcakeep to AMICA.</div>
<div class="">
<div class="">Any ideas?</div>
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<div class=""><br class="">
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<div class="">>> EEG = pop_loadset('filename','pre_p36_nv_to.set','filepath','Processed/');</div>
<div class="">pop_loadset(): loading file Processed/pre_p36_nv_to.set ...</div>
<div class="">Reading float file 'Processed/pre_p36_nv_to.fdt'...</div>
<div class="">>> rank(EEG.data)</div>
<div class=""><br class="">
</div>
<div class="">ans =</div>
<div class=""><br class="">
</div>
<div class=""> 58</div>
<div class=""><br class="">
</div>
<div class="">>> EEG = pop_saveset( EEG, 'filename', 'rankdef.set' );</div>
<div class="">Saving dataset...</div>
<div class="">>> rank(EEG.data)</div>
<div class=""><br class="">
</div>
<div class="">ans =</div>
<div class=""><br class="">
</div>
<div class=""> 1</div>
<div class=""><br class="">
</div>
<div class="">>> rank(EEG.data')</div>
<div class=""><br class="">
</div>
<div class="">ans =</div>
<div class=""><br class="">
</div>
<div class=""> 1</div>
<div class=""><br class="">
</div>
<div class=""><br class="">
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<div class="">
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<div class="">Thanks,</div>
<div class="">John</div>
<div class=""><br class="">
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